James D. Austin

University of Florida | UF · Department of Wildlife Ecology and Conservation

Understanding the epidemiology and transmission dynamics of transboundary animal diseases (TADs) among wild pigs (Sus scrofa) will aid in preventing the introduction or containment of TADs among wild populations. Given the challenges associated with studying TADs in free-ranging populations, a surrogate pathogen system may predict how pathogens may...

Knowledge of the population genetic structure and diversity of at-risk species is essential to accurately evaluate population viability and define units for conservation and management. The southeastern pocket gopher (Geomys pinetis) is a fossorial rodent native to the imperiled longleaf pine savannas of the southeastern United States. Its recent d...

Environmental gradients have the potential to influence genetic differentiation among populations ultimately leading to allopatric speciation. However, environmental gradients can also facilitate hybridization between closely related taxa. We investigated a putative hybrid zone in western Ecuador, involving two polytypic wren species (Aves: Troglod...

Understanding the epidemiology and transmission dynamics of transboundary animal diseases (TADs) among wild pigs (Sus scrofa) will aid in preventing the introduction or containment of TADs among wild populations. Given challenges associated with studying TADs in free-ranging populations, a surrogate pathogen system for in situ studies of pathogen d...

Climate variability influences genetic and phenotypic diversity within species, impacting biodiversity’s evolution. Gene flow and selection maintain changes in genetic and phenotypic variants along an environmental gradient. We investigated a hybrid zone in western Ecuador, involving two wren species (Aves: Troglodytidae), Campylorhynchus zonatus a...

Climate variability can cause genetic and phenotypic diversity within species, which affects the evolution of biodiversity. A balance between gene flow and selection maintains changes in the frequency of genetic and phenotypic variants along an environmental gradient. In this study, we investigated a hybrid zone in western Ecuador involving two spe...

The longleaf pine (Pinus palustris Mill.) savanna ecosystem in North America has declined by 97% from its historic range and its restoration is a conservation priority. The southeastern pocket gopher (Geomys pinetis), an ecosystem engineer in longleaf pine savannas, is absent from most of its historic range. Translocation of pocket gophers may be n...

The coastal waters of Cuba are home to a small, endangered population of West Indian manatee, which would benefit from a comprehensive characterization of the population’s genetic variation. We conducted the first genetic assessment of Cuban manatees to determine the extent of the population's genetic structure and characterize the neutral genetic...

Genetic connectivity lies at the heart of evolutionary theory, and landscape genetics has rapidly advanced to understand how gene flow can be impacted by the environment. Isolation by landscape resistance, often inferred through the use of circuit theory, is increasingly identified as being critical for predicting genetic connectivity across comple...

Knowledge of the genetic structure and cryptic diversity is essential for the conservation of endangered species. We conducted a genetic survey of the federally endangered Florida bonneted bat (Eumops floridanus) sampled from its USA range in southern Florida. Florida bonneted bats are primarily found in four regions separated by approximately 100...

The northern quahog (Mercenaria mercenaria) supports lucrative aquaculture industries in the USA. In the southeastern USA, aquacultured M. mercenaria faces increasing risks of summer die-offs from prolonged heat waves. We used a comparative transcriptomic approach to investigate the molecular responses of M. mercenaria and its southern congener, Me...

Altered weather patterns associated with climate change are likely to adversely affect amphibian recruitment, especially for species dependent on ephemeral, geographically isolated wetlands for breeding. Future changes in temperature and rainfall patterns could affect hydroregimes (periodicity, depth, duration, and timing of water in wetlands) or a...

Largemouth Bass (Micropterus salmoides) are the focus of a billion‐dollar recreational fishery in North America and are subject to widespread hatchery supplementation efforts. Parentage‐based tagging (PBT) uses genetic samples taken from hatchery broodstock to genetically ‘tag’ offspring and represents a valuable approach to inform fisheries manage...

Pocket gophers provide vital ecosystem services; however, species like the southeastern pocket gopher (Geomys pinetis), endemic to the southeastern United States, are declining. Long-term conservation of this species requires greater understanding of its habitat characteristics. Our objective here was to determine habitat features associated with s...

Knowledge of genetic structure is essential for the long-term management and conservation of endangered species. We report the results from a genetic examination of the federally endangered Florida bonneted bat ( Eumops floridanus ) sampled from its range in southern Florida, USA. Bonneted bats are primarily found in four regions separated by appro...

Increased agricultural intensification and extensive woody plant encroachment are having widespread effects on the functioning of grass-dominated systems at multiple spatial scales. Yet there is little understanding of how the provisioning of biodiversity-based ecosystem services might be altered by these ongoing changes. One fundamental ecosystem...

In savannas across the planet, encroaching woody plants are altering ecosystem functions and reshaping communities. Seed predation by rodents may serve to slow the encroachment of woody plants in grasslands and savannas. Our goals for this study were to determine if rodents in an African savanna selectively removed seeds of an encroaching plant and...

The Antillean manatee is categorized as endangered by the International Union for the Conservation of Nature primarily due to its low abundance. Further declines in abundance are expected due to a group of human related threats that include illegal hunting, fatal interactions with fishing gear, increasing watercraft traffic, and pollution. The natu...

Animals living underground deal with multiple physiological challenges, such as hypoxia and hypercarbia, but may have reduced thermoregulation demands because of the more stable underground microclimate. Southeastern pocket gophers (Geomys pinetis Rafinesque) occur in the fire-adapted, open-pine forests of the southeastern Atlantic Coastal Plain wh...

The genus Procambarus represents a diverse genus of freshwater crayfish that includes epigean species, stygobitic species, and at least one parthenogenic species. Despite its evolutionary, ecological, and economic importance, most genomic and transcriptomic resources for this genus are limited to a couple of model species. We sequenced the transcri...

We investigated the landscape epidemiology of a globally distributed mammal, the wild pig ( Sus scrofa ), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmi...

Complicated phylogenetic histories benefit from diverse sources of inference. Pseudacris crucifer (spring peeper) spans most of eastern North America and comprises six mtDNA lineages that form multiple contact zones. The putative Miocene or early Pliocene origins of the oldest lineages within Pseudacris crucifer imply sufficient time for species-le...

For species with geographically restricted distributions, the impacts of habitat loss and fragmentation on long-term persistence may be particularly pronounced. We examined the genetic structure of Panama City crayfish (PCC), Procambarus econfinae, whose historical distribution is limited to an area approximately 145 km2, largely within the limits...

We investigated how herpetofauna respond to burning and burn season in longleaf pine (Pinus palustris Mill.) sandhills by contrasting preburn species richness, diversity, and evenness and captures of six reptile and six amphibian species to the first (Y+1) or second (Y+2) year after burn or between dormant-season burns (DSB) and growing-season burn...

Conversion of native habitats into agricultural monocultures is a major cause of biodiversity loss favouring a small number of generalist species. Rodents can cause significant declines in crop yield, hence understanding the factors affecting their population dynamics is of importance to the agricultural sector. Sugarcane plantations in African sav...

The widespread introduction of Largemouth Bass (Micropterus salmoides) and Florida Bass (M. floridanus) to establish sport fisheries represents a significant conservation concern given their role as apex predators and their ability to alter community diversity and species abundance. In regions like southern Africa, which has both high levels of aqu...

Determining the scale of genetic variation informs studies of dispersal, connectivity, and population dynamics particularly in heterogeneous landscapes. Mastomys natalensis and Mus minutoides are generalist rodents that utilize multiple habitat types within the agro-ecological landscapes of southern African savannas. To study the comparative spatia...

Connectivity is central to ecology and evolution as it focuses on the movement of individuals or genes across landscapes. Genetic connectivity approaches aim to understand gene flow but often estimate it indirectly based on metrics of genetic differentiation, which can also be affected by other evolutionary forces such as genetic drift. Gene flow a...

Live-trapping is important for studying wildlife. In 2016 at Ordway-Swisher Biological Station in Melrose, Florida, USA, we tested the efficacy of a modified pitfall trap designed to safely and effectively capture southeastern pocket gophers (Geomys pinetis). When compared with the commonly used Hart trap, the new design captured 92% of all live ca...

For polytypic mammal species, biogeographic barriers including rivers have often been used to delineate taxonomic units under the assumption that barriers have structured their distribution. We tested the importance of major riverine systems as biogeographic barriers in fox squirrels (Sciurus Niger) across the state of Florida, where 4 currently re...

Abstract Objectively delimiting species boundaries remains an important challenge in systematics and becomes urgent when unresolved taxonomy complicates conservation and recovery efforts. We examined species boundaries in the imperiled freshwater mussel genus Cyclonaias (Bivalvia: Unionidae) using morphometrics, molecular phylogenetics, and multisp...

The greater amberjack (Seriola dumerili) is a commercially and recreationally important marine fish species in the southeastern United States, where it has been historically managed as two non-mixing stocks (Gulf of Mexico and Atlantic). Mark-recapture studies and analysis of mitochondrial DNA have suggested the two stocks are demographically indep...

The status of the West Indian manatee [Trichechus manatus (Linnaeus, 1758)] remains enigmatic. The International Union for Conservation of Nature classifies the species as “Vulnerable” and the two subspecies [T. m. manatus (Linnaeus, 1758) and T. m. latirostris (Harlan, 1824)] as “Endangered.” The U.S. Fish and Wildlife Service now classifies West...

Movement is important for ecological and evolutionary theory as well as connectivity conservation, which is increasingly critical for species responding to environmental change. Key ecological and evolutionary outcomes of movement, such as population growth and gene flow, require effective dispersal: movement that is followed by successful reproduc...

Wild pigs (Sus scrofa) are the most widely distributed invasive wild ungulate in the United States, yet the factors that influence wild pig dispersal and colonization at the regional level are poorly understood. Our objective was to use a population genetic approach to describe patterns of dispersal and colonization among populations to gain a grea...

Florida bass, Micropterus floridanus, is the most popular freshwater sport fish in the state of Florida. Florida bass guard their nests for up to 2 weeks, and many anglers target the prized sport fish during this period using a procedure called bed fishing. This 7-page fact sheet written by John S. Hargrove and James D. Austin and published by the...

An important physiological constraint influencing distributions of coastal freshwater organisms is their tolerance for saline conditions. We experimentally evaluated salinity tolerance for three freshwater mussel species (Utterbackia imbecillis, Elliptio jayensis, and Glebula rotundata). Mussels were transferred abruptly from well water to one of f...

Genetic structure and genetic diversity are key population characteristics that can inform conservation decisions, such as delineating management units or assessing potential risks for inbreeding depression. Evidence of genetic structuring or low genetic diversity in the critically endangered snail kite (Rostrhamus sociabilis plumbeus) would have i...

Context The landscape heterogeneity hypothesis states that increased heterogeneity in agricultural landscapes will promote biodiversity. However, this hypothesis does not detail which components of landscape heterogeneity (compositional or configurational) most affect biodiversity and how these compare to the effects of surrounding agricultural lan...

Integrative taxonomy seeks to approach the complex topic of species diagnosis using independent, complementary lines of evidence. Despite their ubiquity throughout North and Central America, taxonomy of the American leopard frogs (Anura: Ranidae: Rana: subgenus Pantherana) remains largely unresolved, and this is arguably nowhere truer than in the C...

The Florida bass (Micropterus floridanus) is a species endemic to peninsular Florida that is held in high esteem by bass anglers for its tendency to attain a larger maximum size and aggressiveness relative to that of its sister taxon, the Northern largemouth bass, Micropterus salmoides. Hatchery rearing and stocking of Florida bass outside of their...

Black basses Micropterus spp. are the focus of extensive management efforts throughout North America, where they support a multibillion-dollar recreational sport fishery. Harvest rates in many bass fisheries have declined in recent decades, yet a growing number of studies have proposed that catch-and-release angling practices, such as bed-fishing i...

The Largemouth Bass (Micropterus salmoides) is a global invader with demonstrated ecological impacts on native fish communities. Introductions of fishes in freshwater ecosystems are often characterized as complex processes, yet an understanding of the nature of the introduction can inform management and conservation actions. Early in the twentieth...

Grasscutter (Thryonomys swinderianus) is a large rodent distributed across sub-Saharan Africa that is highly valued as a source of protein. There has been little effort to evaluate the genetic structure of grasscutters despite long-term harvesting pressure and over 40 years of grasscutter domestication in West Africa. Our objectives were to quantif...

Understanding mutation rates can greatly extend the utility of population and conservation genetic analyses. Herein, we present an estimate of genome-wide microsatellite mutation rate in Atlantic sturgeon (Acipenser oxyrinchus) based on parent–offspring transmission patterns. We screened 307 individuals for parentage and mutation-rate analysis appl...

Angling for adult black bass Micropterus spp. as they defend nests containing eggs or fry (i.e., bed‐fishing) has drawn concerns from fishery managers and anglers due to negative impacts on reproductive success. Research efforts, however, have failed to consider bed‐fishing scenarios other than male‐directed targeting, which may inaccurately reflec...

The Florida Mouse Podomys floridanus and the Gopher Tortoise Gopherus polyphemus are linked in modern ecosystems by a commensal relationship in which Podomys uses the burrows of Gopherus. However, previous paleoecological research demonstrated that species interactions, including commensalisms, are not necessarily stable through geologic time. Give...

Amphibians that primarily breed in ephemeral wetlands are especially vulnerable to climate change because they rely on rainfall or temperature to initiate breeding and create suitable hydroregimes (water duration, timing, frequency, depth) for reproductive success. Hydroregime effects on reproductive success are likely to differ among species becau...

The decision to disperse or remain philopatric between breeding seasons has important implications for both ecology and evolution, including the potential for carry‐over effects, where an individual's previous history affects its current performance. Carry‐over effects are increasingly documented although underlying mechanisms remain unclear. Here...

Reintroducing native wildlife populations is a common conservation-management approach aimed at reducing the threat of extinction and restoring ecosystem function. Captive-born individuals are sometimes used in reintroductions, but the effectiveness of this strategy is poorly understood due to insufficient post-reintroduction monitoring and evaluat...

In poorly dispersing species gene flow can be facilitated when suitable habitat is widespread, allowing for increased dispersal between neighbouring locations. The Poweshiek skipperling [ Oarisma poweshiek (Parker)], a federally endangered butterfly, has undergone a rapid, recent demographic decline following the loss of tallgrass prairie and fen h...